Workpiece holding clip



M. E. BRINKHAUS WORKPIECE HOLDING CLIP Filed Nov. 25, 1957 Jan. 5

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United States Patent WORKPIECE HOLDING CLIP Matthew E. Brinkhaus,Fresno, Calif.

Application November 25, 1957, Serial No. 698,554

3 Claims. 01. 269-415) The present invention relates to a workpieceholding clip particularly adapted to hold preformed edges of a pair ofsheet members in predetermined association preparatory to and whileinterconnecting such edges.

The utility of the subject invention is conveniently de scribed inconnection with the formation of a sheet metal pipe or duct which iswidely used in the installation of heating and ventilating systems. Sucha duct is usually made from a flat piece of sheet metal bent along lineslongitudinally thereof to provide bottom, side and top walls inrectangular relation to each other. Three of the corners of the duct areintegral but the fourth corner consists of a pair of adjacent edgeswhich must be interconnected in air-tight, relatively rigid anddependable relation.

The conventional manner for seaming the corner of a duct of this natureis by utilization of the Pittsburg seam or joint. In order to providethe Pittsburg joint, one of the walls, a side wall for example, isreversely bent downwardly along a first break line and then againreversely bent upwardly, in simulation of a 2, along a second break lineto provide an elongated pocket extended longitudinally of the duct.Theouter reversely bent flange usually extends above the first breakline a distance substantially equal to the distance between the firstand second break lines. The top wall is bent along a longitudinal lineadjacent to its edge to provide a marginal male flange adapted to bereceived into the pocket of the side wall. After being interfitted inthis manner, the extended portion of the outer flange of the side wallis bent over the adjacent edge of the top wall whereby the edges of thewalls are interconnected.

It is found that while one end of the outer flange along the length of aduct is being bent over against the top wall of the duct, usually byhammering, the opposite end of the male flange frequently vibratesuncontrollably in the pocket thereby tending to dislodge the male flangefrom the pocket throughout the length thereof. In order to obtain asubstantially air-tight, dependable connection, it is necessary that themale flange be held snugly in the pocket while the entire length of theouter flange is being hammered over. If this relationship does notexist, the male flange is loosely held in the pocket, the joint is notsufliciently air-tight, and the duct walls are permitted to shift bothtransversely and longitudinally with respect to each other.

Accordingly, it is an object of the present invention to provide aworkpiece holding member adapted to hold preformed edges of a pair ofsheet members in predetermined association preparatory to and whileinterconnecting such edges.

Another object is to facilitate the edgeward connection of apair ofsheet members.

Another object is to facilitate interconnection of sheet members adaptedto be joined through the utilization of a Pittsburg joint or seam.

' Other objects are to provide a device of the nature described which issimple and economical to construct of the subject invention mounted inpredetermined holding positions along said corner of the duct.

Fig. 2 is a somewhat enlarged end view of the duct and a holding clip ofFig. 1 showing the adjacent wall:

of the corner of the duct preliminary to being joined.

Fig. 3 is a fragmentary somewhat enlarged perspective view of theadjacent walls of the corner of the duct prior to being joined and aperspective view of one of the holding clips attached to the walls.

Fig. 4 is a fragmentary view of the adjacent Walls of the duct afterbeing interconnected by the Pittsburg joint as facilitated by theutilization of the holding clips of the present invention.

Referring more particularly to the accompanying drawing, an elongatedsheet metal duct is generally indicated by the numeral 10. The ductprovides an elongated bottom wall 11, integrally upwardly extended sidewalls 12 and 13 perpendicular to the bottom wall, and a substantiallyhorizontal top wall 14 integral with one of the side walls in spacedparallel relation to the bottom wall.

The duct 10 is formed from a single piece of sheet metal by bending themetal along break lines constituting thecorners between adjacent side,bottom and top walls. In order to complete the duct, the top wall 14must be connected to the side wall 13 and for this purpose a Pittsburgseam or joint 20, as best illustrated in Fig.4, is employed. In order toform this joint, the top wall of the duct provides a downwardly extendedmale flange 22 in right-angular relation to a horizontal inner section23 thereof. For purposes of subsequent reference, a longitudinallyextended, right-angularly bent edge 24 is defined between the innersection and the male flange of the top wall, and the male flangeterminates in a lower edge 25.

Further, the Pittsburg joint 20, insofar as the side wall 13 isconcerned, includes an inner wall portion 28 which issubstantiallyvertical, an intermediate flange 29 integral with the inner portion andreversely downwardly return bent relative thereto, and an outer flange30 integral with the intermediate flange reversely upwardly return bentrelative thereto and terminating in an upper longitudinal edge 31 spacedabove a break line 32 be-' relation with the inner setcion 23 when themale flange IS in the pocket, as described.

. A workpiece holding clip 40, as provided by the present invention,includes an elongated intermediate J-shaped plate 42 having an elongatedshank portion 43 and a lower return bent lip 44 defining a channel 45adapted slidably to receive the male flange 22 of said inner sectionf 23therein. The clip also provides an inner L-shaped plate 43 including amounting wing 49 secured, as by welding, to the shank 43 of theintermediate plate 42 in longitudinally spaced relation to the 'lip 44and a guiding wing 50 perpendicularly laterally outwardly extended fromthe shank and spaced above the base of the pocket 35 a distancesubstantially equal to the length of the male flange 22 so as to overlaythe inner section when the male flange is fitted in the pocket.

Still further, the clip has an elongated outer stepped plate 55including an upper segment 56 secured, as by welding, to the shank 43 ofthe intermediate plate 42 on the opposite side thereof from the innerplate 48, an intermediate oifset segment 57 integral with the uppersegment and laterally outwardly extended from the shank 43 at a positionbelow the guiding win 50, and a lower segment 58 integrally extendedfrom the offset segment in substantially parallel relation to the uppersegment and defining a slot 59 with the shank 43 of the intermediateplate 42.

Operation The operation of the described embodiment of the subjectinvention is believed to be readily apparent and is briefly summarizedat this point. The duct is initially formed to provide the bottom, sideand top walls 11, 12, 13 and 14, and the bends for the Pittsburg joint2% in the top and side walls are provided preparatory to interconnectionof the side and top walls in the manner above described and which iswell-known in the art.

Thereupon, a plurality of the workpiece holding clips 40 are edgewardlyattached to the side and top walls 13 and 14 in longitudinally spacedrelation therealong in the following manner. The shank 43 of the clip isinterposed between the male flange 22 and the outer flange 30 in uprightposition and in substantially parallel relation to the inner portion 28of the side wall. The male flange is downwardly fitted into the upwardlydisposed pocket 35 so that the guide wing 50 overlaps the inner section23 of the top Wall. Thus attached, the clip is longitudinally slidablyfitted on the top wall of the duct. The downwardly disposed slot 59 isthen longitudinally slidably fitted downwardly over the upwardlyextended outer flange 30. The upper edge 31 slidably engages the oflsetsegment 57 of the outer plate 55 limiting relative movement of the sideand top walls toward each other. In this connection the lower end 44 ofthe intermediate plate 42 is slidably engaged with the upper break 32 ofthe side wall at the mouth of the pocket 35 and is sufficiently largerthan the pocket to preclude movement of the intermediate platedownwardly into the pocket. This, of course, also prevents movement ofthe male flange downwardly into the pocket.

A series of the clips 40 are attached to side and top Walls 13 and 14 ofthe duct in the above described manner and are located along the ductfrom the end where the joint is initially to be formed. Accordingly, atone end of the duct from which the nearest clip is spaced, the maleflange 22 is inserted into the pocket 35, and the clamping portion 36 ofthe outer flange 30 is hammered downwardly along a break line 60 intooverlaying engagement with the inner section 23 of the top wall 14.During such hammering, the workpiece holding clips 44) urge the end ofthe male flange downwardly toward the pocket 35. The Weight of thesemembers causes the lower ends of the J-shaped plates 42 to press againstthe mouth of the pocket 35 so that the tendency of the male flange tojump out of the pocket or otherwise to move vertically is minimized. Inaddition, the group of clips precludes lateral movement of the maleflange with respect to the outer flange 30 which is held between theintermediate and outer plates 42 and 55 of the clips. It is to beobserved, however, as best illustrated in Fig. 1, that the inner section23 of the top wall 14 and the clamping portion 36 of the outer flange 30have a slightly upward curvature between the portions of the innersection and outer flange which have been hammered into contact and thoseportions of the inner section and outer flange which have not as yetbeen so hammered. The parts of the outer flange which are bent overagainst the top wall 14 of the duct 1% urges the male flange 22 evenmore snugly into the pocket and thus urges the lower end of theintermediate plate 42 more snugly against the mouth of the pocket.

As the outer flange 30 is hammered over against the outer section 23progressively longitudinally of the duct it), the holding clips 40 aresuccessively longitudinally slidably moved along the edges 25 and 31 ofthe walls 13 and 14. Eventually all of the clips are collected insideby-side relation at the end of the duct and are then removed one byone frorn such end to complete bending over of the outerflange. In thismanner the Pittsburg seam 20 is formed in a more dependable,substantially airtight, and compact association. It is found by usingthe holding members of the subject invention, the tendency of the maleflange 22 to move laterally and/ or elevationally with respect to thepocket 35 is minimized with the result that a vastly superior joint isachieved. Although the duct has been described as being in a horizontalposition and the Pittsburg joint and the clip as having a certainorientation, these positions are not to be regarded as limiting butmerely as exemplifying the preferred utilization of the invention. Theutilization of the described clips not only facilitates the dependableformation of the described seams but enables a sole workman to achievethe formation unassisted by other workmen normally required to hold theseam in assembled condition during completion.

Although the invention has been herein shown and described in what isconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of theinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

l. A tool for aligning a Pittsburgh joint in advance of forming saidjoint between first and second angularly related Walls of substantiallyuniform thickness wherein said first wall provides a male flangeangularly related to an inner section and wherein the second wallprovides a substantially U-shaped pocket in opposed relation to andadapted to receive the male flange and defined by relatively inner andouter flanges, the outer flange being longer than the inner flange, saidtool comprising an intermediate J-shaped plate having an elongated shankportion adapted to be slidably positioned between the male and outerflanges, a lip integrally return bent with respect to and in closelyadjacent spaced relation to the shank portion providing a channeladapted slidably to receive the male flange, the return bend between thelip and the shank portion providing an endwardly tapered wedge-shapedend on the J-shaped plate, said wedgeshaped end having a width greaterthan the Width of the pocket and being adapted to fit against therelatively inner and outer flanges at the entrance to the pocket forholding the male flange in substantially the same plane as the pocketbut preventing the male flange from entering the pocket; a guide memberrigidly connected to the shank portion in longitudinally spaced relationto the lip and laterally extended from the shank portion in opposedrelation to the channel for slidably overlaying the inner section ofsaid first wall thereby to hold the male flange in the channel; and anouter plate segment Connected to the shank portion on the opposite sidethereof from the guide member and extended longitudinally of the shankportion in spaced substantially parallel relation thereto on theopposite side of the shank portion from the lip to provide a slot withthe shank portion slidably adapted to receive the outer flange of thesecond wall, the

a slot and the channel having minimum widths substantially equal to eachother and to the thickness of the walls.

2. The tool of claim 1 wherein the distance between the wedge-shaped endof the J-shaped plate and the point of connection of the outer segmentplate to the shank I portion is substantially equal to the diiferencebetween the lengths of said relatively inner and outer flanges wherebyrelative movement of the male flange and the pocket toward each other islimited by bottoming of the male and outer flanges in the channel andslot, respectively.

3. For use in forming a Pittsburg joint in a corner of a sheet metalduct including first and second substantially perpendicular walls ofsubstantially the same thickness terminating in edges to be connected inoverlapping relation, said first wall having an inner section and a maleflange substantially perpendicularly integrally extended from the innersection, said second wall having an inner wall portion, an intermediateflange integrally return bent with respect to and in contact with theinner wall portion, and an outer flange integrally return bent withrespect, and in spaced substantially parallel relation, to theintermediate flange to provide a female pocket adapted to receive themale flange, the outer flange being extended endwardly beyond the returnbend between the inner wall portion and the intermediate flange to theterminating edge of said second wall and being adapted to be folded overagainst the inner section of the first wall when the male flange is inthe pocket; 2. clip for holding the male and outer flanges in juxtaposedrelation with the male flange in the plane of the pocket but in advanceof fitting the male flange in said pocket comprising an intermediateJ-shaped plate having an elongated flat shank portion longitudinallyslidably positionable between the male flange of the first wall and theouter flange of the second wall wherein said male and outer flanges areon opposite sides of the shank portion and the male flange is out of thepocket, a lip integrally return bent with respect to and in spacedrelation with the shank portion to provide a V-shaped channel having aminimum width substantially equal to said thickness of the walls andslidably adapted to receive the male flange, the return bend between thelip and the shank portion being adapted to fit between the intermediateand outer flanges at the entrance to said pocket thereby to prevent themale flange from entering the pocket; an inner L-shaped plate having amounting wing secured to the shank portion of the J -shaped plate inlongitudinally spaced relation to the lip and a guiding wing laterallyoutwardly extended in substantially perpendicular relation from theshank portion in longitudinally spaced opposed relation to the channelso as slidably to overlay the inner section of said first wall therebyto hold the male flange in the channel; and an outer stepped plateincluding a first end segment secured to the shank portion on theopposite side thereof from said mounting wing, an ofiset segmentintegrally laterally outwardly extended from the upper segment at aposition longitudinally of the shank portion substantially opposite tothe position from which the guiding wing extends, and a second endsegment integrally endwardly extended from the oflset segment in spacedsubstantially parallel relation to the shank portion thereby providing aslot beween the shank portion and the second end segment, said slothaving a width substantially equal to said thickness of the walls andbeing slidably adapted to receive the outer flange of the second wallwhereby the male flange of the first wall is held in substantially theplane of the pocket and to the outer flange of the second wall inadvance of fitting the male flange in the pocket and of folding theouter flange against the outer section of the first wall.

I References Cited in the file of this patent UNITED STATES PATENTS1,409,100 Hamer Mar. 7, 1922 2,200,047 Tinnerman May 7, 1940

